As far as I know the survival aspects are coming later so guns may be interesting in future. At the moment you're right. It is a building game but it is still in development and will not stay like this. I like it as building game but I also like the survival aspect this game may have in future. I think the best way is to play the game as you like best. What I want to say is that even if there are guns in the game doesn't mean you have to use them. But there may be others who want to use them.
Simonk sums it up nicely.
We're basically getting the 'survival' side of the weaponry that you'd expect in a medieval era timeframe, and then a modern era as we tech up into that. We'll start in Medieval era so we'll have bows & arrows, among other things, then we'll gradually tech our way into modern era, or so was Red51's plans. You can also even lock it into eras of medieval only, or modern only. You can expect only survival oriented firearms of pistols, muskets, and such....nothing major. Basically things for hunting & 'self-defense' so you can protect yourself from pirates, bandits, raiders, hostile loggers, wild predatory animals, and other players (if PVP server). Yeah. We're even going to get those canons from colonial era, the ones you see on sail ships from the 1800's. Shall be fun times.
Makes me wonder if we can expect a harpoon gun for when we go swimming in the ocean/water when sharks & such were to be added, only attacking when hungry. Sharks only attack when hungry.....Killer Whales tend to troll a bit......What IS hostile, I wonder.
Survival would also contain what's in '7 Days to Die' of environmental effects of having to stay hot in cold biomes & vice versa. You would get sick from the elements if you don't stay warm in a cold climate, or gain heat stroke when not keeping cool. Even probably getting your character sick when not clothed properly, or dried off from rain, or when coming out of moist areas (lakes). Various sorts.
I mentioned having zombies, but only on the condition that they would be rare & regional. They would only be found in a very rare village on some island somewhere in ruins. They won't wander out, and such....just more of a 'lore' thing. People seem to be so hostile to this idea, even when contained in a region, that it's frustrating. I know people don't want zombies, just that even when contained in a rare manner that people still refuse. It's a shame.
But yeah, Rising World shouldn't be too hard. It's meant to please all player types (casual & hardcore) that everybody shall have fun with it. Red51 is using his common sense, something Mojang struggles with, that he's adding things we desire. He takes things seriously, putting things into the game in a very proper manner while giving us the ability to modify the game however we desire. Make a building only world, or a survival. All up to you.
Sounds promising and already rather enticing! 
. Those lakes are EVERYWHERE! Mostly north & Northeast so far, yet they're EVERYWHERE! I wanted to find another biome, yet was stuck in a repeating lake & the maple-pine 'Canadian Shield' type rocky terrain. Bumpy canyons type thing.
